Electric tester



Jan- 9, 1940 R. scoGGlN 2,186,212

ELECTRIC TESTER Filed Aug. 2, 1958 2 Sheets-Sheet 1 www Jan. 9, 1940. R. L. scoGGm ELECTRIC TESTER Filed Aug. 2, 1938 2 Sheets-Sheet 2 l. stat and as a voltmeter so that not only can the is Provided with 11,1118 40. which carries a screw 'u Patented Jan. 9, 1940 I UNITED STATES' PATENT oFFl'cE Robert L. Scoggin, Ventura, Calif.

Application August 2, 1938, Serial Nth-222,708

Claims. (Cl. 175--183) This invention relates to portable testing despacer I8 and the resistance unit I8 and holding vices used by electricians and test men in making the two socket shells 22 and 28 securely against circuit tests and has for its primary object the the end of the spacer and also holding the cenprovision of a compact, light but sturdy tester tral contacts 25 and 28 -of the two sockets.

I which may be carried in the pocket. These central contacts are respectively insulated Another object is to provi a tester which is from the base of their proximate socket shells of extremely simple design and which may be 22 and 23 by the insulating washers 28 and 2|. easily made up from stock material readily ob- A second insulating washer lll serves to center tainable on the market. the sockets in the tube III.

10 A further object is to provide a tester giving A test cord A is secured to the contact screwzl. visible indications or light signals of differentk 34 which in turn is connected to the central rod intensities to show different circuit conditions. 2! by means of a conductor 88. Thus the test A still further object is to provide a compact cord A is electrically' connected with the center circuit tester which may also be used as a rheocontacts 26 of each socket. The socket shell 22 tester be used for ordinary 110 and 220 v'olt cir- 4| and a spring contact 42. The test cord C cuits but it can be used for obtaining lower voltis secured to the lug by means of the screw 4I ages and for making tests on low voltage delicate and the spring contact 42 provides a detachable circuits. connection for the test cord D. Each of the test I carry out the objects of my invention in a cords is provided with a prong 44 shaped to eno set that is of the same shape and size as the gage between the prongs of an ordinary convenordinary two cell cylindrical flashlight. The set ience outlet and the spring contact blade 42 is consists of two light sockets secured together in ofthe same shape as those found in such outlets spaced relation and having between them a reso as to"receive any one of the prongs 44 on the sistance unit of cylindrical shape all inclosed in test cords. The test cord B is electrically con- 25 a strong fiber case of tubular form which case nected to the socket shell 23 by way of a switch is in turn inclosed in a two part rubber sleeve 45, conductor 48 and the screw 41 but when the that extends a considerable distance at each end switch is open the test cord B is electrically beyond the fiber case so that the set may be connected with the socket shell 23 by way of the 'l r 80 dropped without injuring the lamps in the conductor 48, resistance unit I6, conductor 48 30 sockets. Four flexible cords complete the set: and a screw 41. A lamp, preferably of the 110 three of these cords being permanently secured volt size, is screwed in each socket to complete to the proper contacts and the fourth cord being the set. The lamps and the resistance unit removable to permit changing the circuit conshould all be of the same wattage in order to a8 nections when necessary to carry out desired provide a iiexible test set that may be used for -35 tests.l making the greatest number of different kinds of Figure 1 is a central longitudinal sectional tests without changing the lamps for lamps of view of the tester. different sizes. Y

Figure 2 is a sectional view taken on line 2-2 The new set may be quickly assembled be- 40 of Figure 1. cause of the simplicity and the symmetry of ar"- .0

Figure 2a is a view of a modification of the rangement of the parts; The shells 22 and 28 are secured to the rectangular spacer I8 by means of Figure 3 is a fragmentary view of the casing. the bolt 20 which is first threaded through the Figures 3a to 7 are circuit diagrams showing resistance unit I6 and other elements before apa the device connected for diilerent tests. Dlyins the nut to hold the parts 0f the bOdy 45 Referring to Figure l, a fiber tube i0 of strong in assembled relation as shown in Figure 1. The insulating material is centrally located within a conductors are then attached to the terminals rubber casing i2 which casing is made of two 34, 4I and 41 and the thus assembled parts are cylindrical sleeves contacting each other at the inserted in the tube I 0, the conductors being 50 middle I4 of the set. Centrally located in the threaded through apertures provided in the tube 50 tube III is a fiber spacing element I8 which is wall. Three of these conductors, 48, 48 and B preferably ayrectangular frame surrounding and are threaded through the switch receiving opensupporting a resistance unit IB of the usual ing 52. The body is then turned in the shell until cylindrical shape. The resistance unit is held the terminal 42 registers with the opening I4 at in the frame by a bolt 20 passing through the which time a set screw 5I is inserted to prevent -lili further movement of the body in the tube Il. The sleeve aidsin holding the set screw IB in place'and at the same-time insulates it from accidental contact. 'Ihe switch 48 is now connected to the conductors 46, 48 and B and is then secured to the tube in the opening 52 and the two parts of the sleeve I2 are pushed over the tube into abutting relation. The rubber sleeve is split longitudinally as indicated at I8 in Figure 3, and in addition apertures 59, 60, 6I and i2 may be provided for the switch l5 and the test cords A, B. C and D. Instead oi the rectangular spacer I8 I iind it sometimes desirable to use a spool-shaped element such as Ita shown in Figure 2a. the resistance wire being wound directly on the spool.

'The method of using my test set is diagrammatically indicated in Figures 3a to '7. In Figure 3a is shown the manner of testing for current in a circuit, only one lamp being used, (lamp M) if a 120 volt circuit, but both lamps being used as shown in Figure 3b ii' a 240 volt circuit.

In Figure 3c the switch 45 is shown in open position for testing a 550 volt circuit. The lamps in Egure 3b will begin to glow visibly if twenty volts are on the line but will be of full brilliance at 240 volts and with a'little practice one may roughly judge the voltage oi the line by the degree of brilliancy of the lamps. 'I'he same is true when the lamps are connected as shown in Figure 3c except that the rst visibility occurs at about iiity volts and full brilliancy will be had at 550 volts. 'Ihe lamps may be observed from the ends of the casing or through the apertures 53 provided in the casing walls.

The method of testing appliances for open or short circuits is shown in Figures 4o to 4c. In VFigure 4a the test cords B and C are inserted in the spring terminal 42. This hook-up gives 60 volts across the test cords A and D, which is sutilcient to test an ordinary appliance. If the circuit indicated at 62 is shorted then the lamp M will be extinguished and lamp N will become brighter but if the circuit 62 is open no change will be noted in the brilliancy of lamps M. For making tests of more delicate circuits the switch I5 is open which connects the resistance I6 in series with the lamps and provides 25 volts across the test cords A and D. By inserting the test cords A and C in a convenience outletas shown in Figure 4c, 120 volts is obtained across the test plugs B and D but the amperage is cut down about two-thirds.

'I'he diagram in Figure 5a shows the method of connecting a circuit SIto .be tested'in series with the lamps M and N or when switch I5 is open the resistance I6 is added in series with the lamps; in this test the cord A is not used. In

' Figure 5b the prong of the test cord Bis inserted in the terminal I2 which puts lamp N in parallel with lamp M for making certain tests requiring more current. 'Ihe diagram shown in Figure 5c is similar to that shown in Figure 5a except that lamps M and N are connected in parallel for giv- -ing additional current in testing a circuit Si.

In Flgure the method is shown for protecting the test set by substituting a fuse III for one oi the lamps, for example, lamp M. This connection is used on rare occasions for testing a circuit of unknown voltage.

In Figure 7 is shown the method oi determin- 4ing which side of a llne is grounded. The test cords B and C are connected to the two lines 12 and 13 then the test cord A is touched to ground. Ii' lamp M glows and lamp N is extinguished this indicates that line I2 is grounded. It lamp N glows and lamp M goes out this indicates that the other line is grounded.

What I claim is:

1. In an electricians test set a tubular casing, a lamp socket operatively mounted in each end of the tube, a spacer between said sockets, a resistance element supportedliy said spacer, a straight electrical conductor positioned axially of the element and spacer for connecting said sockets together and to the spacer and a plurality of test cords electrically connected to the sockets and to the resistance element.

2. '111e device of claim 1 in which said spacer is a hollow frame and the resistance element is carried in said frame.

3. In an electrician's test set a tubular casing, a lamp socket operatively mounted in each end of the tube, a spacer comprising a rectangular frame located between the sockets, a bolt passing centrally through the frame and connecting the sockets together and to the frame, a resistance element held in the frame by the bolt, and a plurality of test-cords connected respectively to the sockets and to the resistance element.

4. The device of claim 1 in which a switch is provided for short circuiting the resistance.

5. In a test set a rigid tube of insulating material, a lamp socket operatively mounted in each end of the tube, an insulating element between the sockets, a resistance coil supported on the insulating element, a bolt passing centrally through the coil and through the element for means connecting the sockets to each other, electric conductors connecting the sockets and the resistance coil, test cords conected to said coil and sockets and a iiexible casing around said tube and projecting beyond each end, said casing being provided with apertures for permitting observation of lamps in said sockets.

6. The device of claim 5 in which each test cord is provided with a terminal prong adapted to iit in the usual convenience outlet, and a spring terminal electrically connected to the shell of one of said sockets for receiving any one of said prongs.

7. In a test set a pair of oppositely facing sockets each having a central contact, a spacer between and supporting said sockets, a bolt passing through said spacer and mechanically and electrically connecting said central contacts and a resistance coil mounted on said spacer. 8. The device of claim 7 in which said spacer is a hollow frame and said coil is held in said frame by said bolt. said bolt being removable to permit the easy installation and replacement of the sockets or the coil.

9. In a test set a pair of sockets each having a central contact, a spacer between said sockets, a bolt passing through the spacer and connecting said central contacts, a resistance coil carried by said spacer, said coil being electrically connected to the shell of one of the lamp sockets, a test cord electrically connected to said bolt, a test cord electrically connected to said coil, a test cord electrically connected to the shell of the other socket, a switch for short circuiting said resistance coil and a spring terminal for receiving the prong of any of said test cords.

10. An electrician's test set comprising a rubber casing, a ilber shell having a friction nt in said casing, a pair of lamps operativelymounted in said shell in spaced relation, a resistance unit removably mounted in said shell, a pluralityot test cords through the wall of the casing and shell and electrically connected with said sockets and said resistance coil, a switch mounted on said shell for short circuiting said resistance, each oi' said cords having a test pi'ong shaped to fit the terminals oi' a convenience out- ROBERT L. SCOGGIN'. 

